<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title></title>
    <style>
        #div1{
            width: 100px;
            height:100px;
            background: skyblue;
            box-shadow: 2px 2px 4px #ccc;
            border-radius: 50%;
            position: absolute;
            bottom: 0;
            right: 0;
        }
    </style>
</head>
<body style="height: 2000px;">
   <div id="div1"></div>

   <script type="text/javascript" src="js/util.js"></script>
   <script>
       var oDiv = document.getElementById('div1');

       window.onscroll = function () {
           var scrollTop = document.documentElement.scrollTop || document.body.scrollTop;
           var iTop = document.documentElement.clientHeight - oDiv.offsetHeight +scrollTop;

           startMove(oDiv,{top:iTop});

       }
   </script>
</body>
</html>